LaMnO3, and gel films were deposited by spin-coating technique on scandium-doped zirconia (YSZ) substrate using the precursor solution prepared from , or ,2-methoxyethanol, and polyethylene glycol. By heat-treating the gel films, the electrochemical cells, were fabricated. The effect of polyethylene glycol on the microstructure evolution of and thin films was investigated, and NOx decomposition characteristics of the electrochemical cells were investigated at to . By applying a direct current to the electrochemical cell, good NOx conversion rate could be obtained relatively at low current value even if excess oxygen is included in the reaction gas mixture.